I'd agree with everyone recommending the rayon, I've given up on JC in favor of it, it tastes better to me. However switching to rayon won't make you wick any better.
When I'm wicking I'll take what I hope is the right amount and then gauge it by squeezing it between 3 or 4 fingers just to see how thick it will end up once compressed. Do that a few times and you'll get better and better at guessing what is the right amount to start with. When dry rayon is more slippery than JC and after compression will spring back up as opposed to holding any of its compressed shape. I don't stretch it and don't do Scottish rolls, I just take a piece about the right length and separate/thin it as necessary, give it a roll or two between my fingers and then start rolling the one end to get it through the coil as normal. I've seen various recommendations on different ways to wick with rayon including cutting much of it back on either side of the coil leaving only small wicks to the juice. Some suggest putting in very tight through the coil but I just avoid it being loose otherwise it dosen't seem to matter that much as to whether it is just snug or tight. I pretty much wick the same way as I did with JC and it seems to work fine. The only exception to this is in my Theorems where I thinned the tails considerably so the is more room for the juice in the tank instead of mainly rayon tails.